Apparatus for continuous blow down for boilers



Aug. ll, 1931. j L. D. KENslG 1"818483 APPARATUS FOR CONTINUOUS BLOW-DOWN FORv BOILERS y Filed Aug. 9, 192s s sheets-sheet 1 Aug.,11, 1931. L. D. Kr-:NslG 1,818,483

l APPARATUS FOR OONTINUOUS BLOW-DOWN FQR BOILERS Filed Aug. 9, 1928 3 Sheets-Sheet 2 L. D. KENSIG Aug. l1, 1931.

' APPARATUS FOR CONTINUOUS` BLOW-DOWN Fon oILERs Filed Aug'. 9. 1928 s sheets-Sheet 5 `the injector A5 Patented Aug. 11, 1931 UNITED STATES PATENT" OFFICE LOUIS D. KENSIG, 0F WESTERN SPRINGS, ILLINOIS, ASSIGNOR TO NATIONAL ALMI- NATE CORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS APPARATUS FOR CONTINUOUS BLOW DOWN FOR BOILERS Application filed August 9, 1928. lSerial No. 298,422.

My invention relates to improvements in apparatus for continuous blow downl of boilers and the like and has for one object to provide a new and improved blow down ap-v paratus wherein the amount of water blown down by any one or all of the boilers in the battery Whether working together or separately is automatically controlled. Another Aobject is to provide means whereby the amount of blow down water leaving the boiler is automatically coi-elated and controlled by and with the amount of 'feed water entering the boiler. Another object is to provide means in coordination with the automatic control of each individual boiler for controlling the total amount of blow down water leaving the system'. Other objects will appear from time to time in the specification and drawings.

My invention is illustrated more or less diagrammatically in the accompanying drawings wherein- Figure 1 illustrates a battery of boilers with heat exchanger, pre-heater and injector;

Figure 2 is a section through the heat exchanger showing manual boiler control in elevation; l

Figure 3 is a section through the automatic control valve; j

Figure 4 is a side` view of the automatic control valve.

Like parts are indicated by like characters throughout.

A A1 are two of the battery of boilers. A2 is a heat exchanger, Aa is a feed water heater. A4 is a feed water pipe leading to and thence to the discharge pipe A8 from which lead branches A7 A8 to boilers A A1 respectively, controlled of course by the valves A9 which may be turned off when the boiler is out of operation.

Discha-rging from each of the boilers at a point just below the water line are blow off pipesB B. These pipes lead to and are `controlled by automatic valves B1, which valves are responsive in their operation to the inflow of feed water as will hereinafter appear, and control the amount of water running 0E from the boiler. Pipes B8 B3 lead from these valves to the blow off manifold B". This blow Athere being a plurality of off manifold is controlled by and adjustably loaded continuous blow down valve B, and extends into the heat exchanger tank B", discharge orifices B7 through which the water from the manifold B4 is discharged into the tank B at a number of points. Leading from the bottom of this tank is a run oli' pipe B8 controlled by a constant pressure valve B". This pi extends into the heat exchanger tank B- and is provided with a series of perforations B1o so as to draw water off from the bottom of the tank at a number of points thereby permitting free and easy straight line iow of the hot blow down water from the top to the bottom of the tank. The pipe BR discharges to the sewer and the foul blow off water is wasted therethrough.

The heat exchanger tank is fianged at the top as at C, at the bottom as at C1. C2 is a tube sheet, C3 a fianged water drum, the drum flange, the tube sheet and the tank flange C1 are all fastened together so that a closed make up feed water chamber C4 is provided at the bottom of the tank B adapted to receive cold make up 'feed water from the pipe C5. f Straight heat exchanger tubes C6 are mounted in the tube sheet C2 and at their upper ends are also mounted in a tube sheet C7 which is flanged as indicated to engage a bonnet C8 which in turn communi- Cates with a hot water make u pipe C9 passing out through the wall of tige tank B and leading to the feed water heater. This pi e is flanged as at C1 and there isa packing 11 to make a water and steam tight joint where the pipes asses out from the tank.

It will e noted that the flange C7 and the bonnet C8 are free from contact Vwith the inner Walls of the tank Be and water may circulate about the flangesv and the water level in the heat exchanger tank will be above vthe bonnet C8 and pipe C. D is a float sup- 'stem toward and from the seat D. The vapor pipe permits discharoe of vapor or steam from the vapor cham er D1. When the water line is as shown in the figure the float is down low enough to permit opening of the valve D3 and vapor can pass out through the vapor pipe D7 to be discharged into the feed water heater. If the water level in the tank B6 rises, the iioat will be lifted and close the valve thus preventing discharge of water through the vapor pipe.

Experience shows that different boilers for some reason or other require different rates of blow off, therefore the operator by testing the water in the individual boilers can ultimately arrive at a proper setting of the variable orifice control for each boiler.

If we say for instance we have 150 pounds boiler pressure, the pressure in the line beyond the variable orifice control will perhaps be 145 pounds. The spring loaded blow down valve Bi may be set to control the blow off and bring the pressure down to five or ten pounds gauge. This water flows into the heat exchanger. Most of its passes down along the heat exchanger tubes giving up its heat to the cold incoming feed water,

Y passing the constant pressure valve which for instance will be set at three pounds static head and is discharged to the sewer. Above the bonnet at the top end of the heat exchanger tank will be some of the blow off water. The pressure in the tank will be to from two to live pounds or even less. When the water at boiler pressure and temperature is discharged through the blow down valve into the heat exchanger tank at pressure but slightly above atmospheric as above indicated the sensible heat of the water is dissipated in the production of water vapor which passes olf from the blow down water into and from the vapor chamber and eX- perience shows that the water vapor thus discharged amounts by weight to from iifteen to twenty percent or sometimes even more of the blow down water depending upon the boiler pressure carried, the greater' the boiler pressure, the greater the percent of vapor. This vapor passes out through the pipe from the vapor chamber and since 1t is ure steam without impurities may be used or any purpose for which low pressure steam is desired as for instance for industrial purposes or` for addition to the make up water.

The cold water passing in at the bottom of the tank comes up through the heat exchanger tubes traveling in a direction opposite to the blow off water, is heated by the blow off water and discharged ultimately to the feed water heater in the form of partially heated water.

The heat of the blow off Water is thus used in two ways in connection with the make up water. The heat is used when the pressure is reduced to cause vaporization. The Vapor passes oii' and is used. An appreciable amount of heat is thus saved and pure or distilled water is thus provided from the blow off water, the temperature dropping from boiler temperature down to approXimately 212 at the heat exchanger tank.

The remaining blow off water at approximately 212 passes down toward the discharge coming in contact with and surrounding the pip-es containing the make up water and giving up its heat to the point where the blow off water as it leaves the tank is but slightly warmer than the make up water as it enters the tank.

The automatic control valve is the same for each of the boilers and a description of one will suffice for all. The feed water enters the housing in the direction of the arrow X shown in Figure 8. It lifts the poppet Valve F against the compression of the spring F1 permitting the flow of feed water through the valve. The upward movement of the valve F carries with it the valve stem F2 and this lifts the blow off needle valve F3 away from its seat F4 to permit blow off water to run out in the direction shown in the arrow Y. The movement of the valve F in response to flow of feed water may be cont-rolled by tension of the spring F1 and the relation of th two valves may be adjusted by changing the size of the valve parts or by providing different length valve stems. This adjustment is made once and for all and is made with or soon after the original set up of the boiler. and so no provision is provided or needed for change in adjustment during the operation of the boiler plant.

The reason for this is that experience shows that tests made of the boiler at an early stage show just what relation is required between blow off and feed water. lished and the automatic valve adjusted for that purpose no further change is required.

Where I have used the term valve in the specification and claims it will be understood that the term is used in a very broad and general sense and does no* imply actual, positive. complete closure or shutting-off or arresting of flow of water. The structures that I have used are valves in the generally accepted commercial sense. but they do not have to and ordinarily never actually do prevent water flow; these valve structures merel control the rate of iow and may be so a justed, operated and set as to do this, and so as to maintain the desired relation between infiow and outflow of the water in the various situations where these Valves are placed for the purpose of carrying out my invention.

I have illustrated a spring-loaded valve and have so described it but it will be understood that by the use of the term spring as applied to the loading of the valve, I do not intend to be limited to a mere mechanical coil spring as illustrated. Any element havthe feed water as to.

valve adapted to control the ing a spring eect, no matter how that spring or yielding resistance to valve movement is effected, is a spring loading means for the valve in t e sense in which I use the term.

I claim: 1. In combination,

a boiler, a feed water plpe, and a blow oil' pipe for the boiler, a

'valve adapted to control the ratevof ow through the blow off through the blow off pipe, a member in the feed water pipe so interposed in the path of the feed water as to be displaced according to the rate of flow of the member being so directly connected to the valve in the blow off pipe as to control the rate of flow of the blow off water, a heat exchanger into which the blow olf water is "discharged, and through which the feed water 'is fed, means for positively forcing feed water through the pipe and a separate control Avalve interposed between -member in the path of flow of feed water.

3. In combination, a plurality of boilers, a Ifeed water pipe, branches leading from it to each boiler, means for forcing feed water to and through said pipe, a blow 0H -pipe for each boiler, a separate valve associated with the blow olf pipefrom each boiler to control the blow oif inv each branch of the feed water pipey leading to a boiler adapted to be displaced by the flow of feed waterin each branch there being a direct mechanical connection between the member in the feed water pipe branch and the blow oil pipe associated with each individual boiler whereby displacement of the member in the feed water pipe branch displaces the blow olf valve of each boiler to control the blow oill from each boiler in consonance with the rate of flow of the feed water of each oiler, yielding means adapted to hold both the blow off valve and the member in the feed water pipe branch of the same boiler in closed position, said yielding means adapted to be overcome by a predetermined pressure of feed water to lift the member in the feed water pipe off its seat to permit flow of-feed water.

4. In combination with a boiler, a feed water pipe and a blow olf pipe, a manually adjustable control valve in each, an automatically controlled valve in the blow olf pipe, l

and a vane located in the feed water pipe adapted to be displaced by the flow of feed water, a direct mechanical connection between the vane located in the feed water pipe and \the said automatically controlled valve in the feed water, saidy the boiler and the blow olf pipe whereby movement of the vane in the feed water pipe responsive to the flow of feed water causes displacement of the blow oil valve.

Signed at Chicago, 'county of Cook, and State of Illinois, this 7th day of August,

LOUIS D. KENSIG.

therefrom and a member located 

